Abstract

An ex situcleaning and etching technique was applied to NaCl single crystals to prepare atomically flat and clean NaCl surfaces. These were used as substrates for molecular beam epitaxial growth of ultrathin continuous Bi(111) films. The high film quality—as studied with low energy electron diffraction,atomic force microscopy, and transmission electron diffraction—is attributed to the commensurate 10:7 ratio of the lattice constants. Dissolving the NaCl substrates in water allows the fabrication of freestanding 20 nm thin Bi(111) membranes of centimeter size.